I. Field of Invention
The present invention relates to an exercise apparatus in general and, more particularly, to an inclination controlling device of a treadmill and foldable treadmill using the same, the treadmill inclination angle can be controlled more widely including a downward inclination as well as an upward inclination in order to enable users to run or walk on the treadmill in various conditions.
II. Description of Related Art
A treadmill known as a running machine is widely used indoors such as at home or in a sports center as it allows users to have an effect of exercising while working or running on its endless rotating belt in a narrow space. Recently, the demand for treadmills is drastically increasing due to the advantages of its safety and convenience because users can exercise indoors using the treadmill even in the cold winter.
Users of a treadmill can strengthen their cardiopulmonary function and leg muscles, and can control their weight by consuming calories efficiently while running or walking on a treadmill. To maximize this exercise effect, a treadmill with an inclination controlling device has been produced lately.
A treadmill comprises a foot plate which upholds load resulting from users, a belt rotating endlessly around the footplate on which users can run or walk continuously, an operating motor for the belt, a holding post used as arm supports while exercising, an inclination controlling device which supports the load of the footplate and controls the inclination.
As illustrated in FIG. 1, the conventional treadmill 1 includes a support frame 10 which upholds weight or impact by running or walking thereon, a link member 20 pivotally connected to one end 11 of the support frame for rotating relative to the support frame 10, a fixed member 30 which is connected to the support frame 10 to uphold a rear part of the support frame 10, a base 40 pivotally connected to one end 21 of the link member 20 for rotating and settling on the ground, an actuator 50 which connects the base 40 with the link member 20.
The fixed member 30 has one end 31 welded to a support frame 10, the other end 32 which maintains a constant angle with a ground, and a roller 32a on the ground movable with a support frame 10 according to an operation of the actuator 50.
The actuator 50 has one end 51a pivotally connected to a link member 20 for rotating relative to the link member 20 and can control an inclination angle of the support frame 10 by means of contracting or extending a bar 51 because the bar 51 controls an angle between the link member 20 and the base 40 thereby allowing the link member 2 to rotate relative to the base 40.
In the conventional treadmill shown at FIG. 1 as described above, the angle θ between the link member 20 and the base 40 gets smaller and the height of the joint 11 gets lower while the bar 51 of the actuator 50 is being contracted. On the contrary, while the bar 51 is being extended, the angle θ gets bigger and the height of a joint 11 gets higher. As a result, the treadmill can have various slope for running or walking.
However, the inclination controlling device of the conventional treadmill counts on a height deviation amount of the joint 11 caused by a rotation of the link member 20 in view of controlling the inclination angle of the support frame because the distance from the joint 11 to the ground is consistent regardless of operation of the actuator 50. Therefore, the conventional treadmill is limited in that it cannot control the inclination angle in a wide range.
Besides, the fixed member 30 should be formed short to make a steep inclination angle in the conventional inclination controlling device. But in this case, the conventional treadmill cannot substantially provide a downward inclination because of the short length of the fixed member 30. Moreover, in the case of the steep inclination of the support frame 10, moments are concentrated near the actuator 50 thereby causing weakening of the durability of links.